linux-kernel - Re: [PATCH v5 0/3] mm: ZSWAP swap-out of mTHP folios

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Message-ID: <CAKEwX=Nak1J30bDmavQZH3SrcmP9hj2X7wYg-eX=k-jb_p+T=g@mail.gmail.com>
Date: Thu, 29 Aug 2024 16:47:58 -0700
From: Nhat Pham <nphamcs@...il.com>
To: Yosry Ahmed <yosryahmed@...gle.com>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@...el.com>, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org, hannes@...xchg.org, ryan.roberts@....com, 
	ying.huang@...el.com, 21cnbao@...il.com, akpm@...ux-foundation.org, 
	nanhai.zou@...el.com, wajdi.k.feghali@...el.com, vinodh.gopal@...el.com
Subject: Re: [PATCH v5 0/3] mm: ZSWAP swap-out of mTHP folios

On Thu, Aug 29, 2024 at 4:39 PM Yosry Ahmed <yosryahmed@...gle.com> wrote:
>
> Interesting. If CONFIG_THP_SWAP is enabled this basically means your
> zswap utilization keeps going down as your THP utilization goes up. So
> the swapin cost would go higher. How do you deal with that?

Johannes definitely knows more than me about this, so please fact
check me. But my understanding is we don't get enough THP for this to
become a problem just yet :)

But yes, we're working hard to make THP become more readily available.
Which will lead to the problem you're describing, hence my enthusiasm
in this work :)